Crestron Avia DSP
At Utah State University we typically use audio DSP devices
in distance learning capable classrooms. We have experience with a variety of
these devices, and have an install base of more than 150 Cisco codec equipped
classrooms on our main campus and across the state at satellite campuses and
learning centers. Over time, we have deployed devices from a variety of
manufacturers – Polycom Vortex, Biamp Nexia, and BSS Soundweb.
We rely heavily
on Crestron control and video switching in our installations, and so were very interested
in the new Crestron Avia DSP. We have installed a handful of these DSP’s in
rooms on our main campus as part of a recent classroom technology upgrade. One
installation provides the audio mixing and routing for a distance learning
classroom equipped with a Cisco SX-80, Crestron processor, Crestron video routing
and Shure steerable ceiling array microphones.
Hardware
For this installation we used the DSP-1283, a single rack
unit box with 12 analog in, 8 analog out, 32 channels of Dante, SIP/POTS telephone
I/O, 2 channels of USB I/O, and 8 internal ’Aux’ busses (more on those later),
and AEC. The chassis has front panel bargraph meters for the analog inputs and
outputs. Our room audio sources are a wireless instructor lavalier, two Shure
MXA910 ceiling arrays, and line inputs from room media sources. Outputs feed
the Cisco codec microphone input, presentation content line in, PC audio in for
lecture capture, and two stereo amplifiers for 4 speaker channels. The Avia
devices are fixed architecture DSP’s The processing blocks are preassigned to
channel strips and analog outputs, and the processing objects are available on the
analog I/O and aux bus inputs only.
Performance according to published specs is good, with
24-bit A to D, 110 db dynamic range, Equivalent input noise of -125db, and an input
gain range of 66db which exceeds the available input gain of 48db on the BSS
devices and could be helpful in some situations.
Setup
Network setup was simple. In our operation, we run all
devices in DHCP, but use our enterprise network management tool to assign
static IP addresses where needed, and we assign all Crestron devices to their own
VLan. Because this DSP has a Dante interface, it has a second MAC address , and
requires a second IP address for the Dante network. The software tool has
device discovery, or you can manually input IP addresses for communication
across subnets.
Software
For Crestron users who will tie this into a control system,
the devices’ Crestron net ID (IPID) is set in Toolbox, but all other configuration
is accomplished through the stand-alone application - Crestron Avia Tool which
installs in your Toolbox folder if you have installed other Crestron software.
There are a few nagging issues in the user interface,
undoubtedly most can be attributed to the fact that this is a new product.
The interface has a single main view, but separate signal and
system view tabs.
In System View input
and output meters are available, crosspoints can be muted, and levels viewed
for each crosspoint by hovering the mouse. A double click will mute a crosspoint,
but the crosspoint levels may not be adjusted. This view also shows a list of available
devices.
Signal view allows
adjustment of crosspoint levels and mutes. A single click brings up a numerical
db level display with up/down level adjustment arrows, or a right click brings
up a slider with copy, paste, undo and crosspoint mute buttons. Here you can
copy your level settings and paste to another crosspoint, but this requires you
to open the destination crosspoint with another right click, and select the
paste button. Windows shortcut keys (CNTRL C, CNTRL V) do not work, and levels
may not be pasted to a range of destinations at once.
Channel names are visible on a toggle, but toggling the name
view on in the system view does not make them visible in other views, you must also
turn them on in signal view if you want them to remain visible as you change
views
Input and output rows are numbered, but crosspoint columns are not
numbered. A small complaint, but you must either count across or hover the
mouse to check the output crosspoint number
Open the help file, and the window opens and stays in focus
– you must close it again before working on whatever you needed the help for in
the first place
Beware of the dual input mutes – analog inputs have an input
gain module with its own mute. This is separate from the channel mute, and is
visible in the system view, but not the signal view unless you open the channel’s
input gain block.
A potentially large issue with the fixed architecture - full
DSP blocks are available on only the 12 input channels. This device has 32
channels of Dante available, but it is only matrixed. A Dante input must be
assigned to one of the 12 channel strips for full DSP features to be available.
It is important to be aware of this as you design your system, this device is
limited to 12 input channels and 8 output channels for anything other than
simple routing and level control. Other flexible architecture DSP’s we have
used do not have this limitation, allowing processing of up to 64 channels of Dante
without adding additional boxes. A large system using one of these other devices
could be considerably less expensive than the multiple Avia
boxes that would be needed for a similar channel count.
Finally, the Aux busses. A bit of an odd feature as
implemented. These are not your mother’s aux busses. They do not function as an
audio engineer would expect an aux to operate. There are 8 aux sends which seem
to be intended to be used as group submasters. Auxes, labeled as Inputs and Outputs
are internally bussed, output tied to input, almost like an insert loop or an
aux buss brought back to input strip. Signal can be sent from any channel strip
or Dante input to an aux bus. The signal then routes automatically to the
corresponding aux in. The aux in strips have DSP available and the matrix
allows routing with level and mute control to any output, so this does allow a
way to expand processing capacity and grouping and processing of input channels.
Crestron interface
Arguably the biggest reason to choose these devices is the
integration with other Crestron hardware. Crestron has developed a neat UI
export tool which will create touchpanel smart graphics objects automatically, which
can then be added to your touchpanel project. These objects can communicate
directly to the DSP while adding only minimal support in a Simpl program.*
In Simpl windows, the default control symbols for the Avia
DSP’s are fairly complete, but missing crosspoint level or mute controls.
Bottom line
Good integration with Crestron, and very usable in a smaller
installation. The advantages in a system exceeding 12 analog inputs or
requiring multiple channels of Dante are not as great. Software is a good first
implementation, and I eagerly await updates for some needed improvements. Cost
on these devices ranges from $2000 to $4000 list, and seems reasonable,
especially when the benefits of the Crestron integration features are factored
in.
*Updated after more time to test with the box - Simpl integration requires the import of one module to carry CRPC data. On program initialization, communication is established between the touchpanel and the DSP, requiring no further processing in the system program. Also, controls created in the UI export tool are used in the VTPro-e project but do not produce a custom module for use in the Simpl program. Did I mention crosspoint level and mute contol is needed in Simpl?
Hey, I love the meters, though...
